:root {
  color-scheme: light;
  font-family: "Segoe UI", Tahoma, Arial, sans-serif;
  line-height: 1.4;
  color: #1f2933;
  background-color: #f6f8fb;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  padding: 24px;
}

.app {
  max-width: 920px;
  margin: 0 auto;
  display: grid;
  gap: 18px;
}

.app-header h1 {
  margin: 0;
  font-size: 1.8rem;
}

.app-header p {
  margin: 6px 0 0;
  color: #566474;
}

.brand {
  display: flex;
  align-items: center;
  gap: 14px;
}

.brand-logo {
  width: 90px;
  height: 90px;
  object-fit: contain;
  border-radius: 8px;
  background-color: #ffffff;
  border: 1px solid #d6dde6;
  padding: 6px;
}

.controls {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  align-items: flex-end;
  padding: 14px;
  border: 1px solid #d6dde6;
  border-radius: 8px;
  background-color: #ffffff;
}

.control-item {
  display: grid;
  gap: 8px;
  min-width: 220px;
}

.control-item select {
  height: 36px;
  border: 1px solid #b7c4d4;
  border-radius: 6px;
  padding: 0 10px;
  background-color: #ffffff;
  font-size: 0.95rem;
}

.export-btn {
  height: 36px;
  border: 1px solid #2563eb;
  background-color: #2563eb;
  color: #ffffff;
  border-radius: 6px;
  padding: 0 14px;
  cursor: pointer;
  font-size: 0.9rem;
  font-weight: 600;
}

.export-btn:hover {
  background-color: #1d4ed8;
  border-color: #1d4ed8;
}

.grid-section,
.formula-section,
.results-section {
  padding: 14px;
  border: 1px solid #d6dde6;
  border-radius: 8px;
  background-color: #ffffff;
}

.data-grid {
  width: 100%;
  border-collapse: collapse;
  table-layout: fixed;
}

.data-grid th,
.data-grid td {
  border: 1px solid #c6cfda;
  padding: 0;
}

.data-grid th {
  background-color: #edf3fb;
  padding: 10px 12px;
  font-weight: 600;
  text-align: left;
}

.data-grid input {
  width: 100%;
  height: 38px;
  border: 0;
  padding: 8px 12px;
  font-size: 0.95rem;
  background: #ffffff;
}

.data-grid input:focus {
  outline: 2px solid #4b8ad8;
  outline-offset: -2px;
}

.data-grid input.invalid {
  background-color: #ffe5e5;
}

.data-grid input.selected-cell {
  background-color: #e8f1ff;
  box-shadow: inset 0 0 0 2px #4b8ad8;
}

.grid-hint {
  margin: 10px 0 0;
  font-size: 0.9rem;
  color: #556677;
}

.formula-section h2 {
  margin: 0 0 8px;
  font-size: 1.1rem;
}

.formula-list p {
  margin: 8px 0;
}

.formula-list p:nth-child(odd) {
  font-weight: 600;
  color: #334155;
}

.formula-list mjx-container[display="true"] {
  text-align: left !important;
  margin: 0 !important;
}

.results-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

.result-card {
  border: 1px solid #cbd5e2;
  border-radius: 8px;
  padding: 12px;
  background-color: #f9fbff;
}

.result-card h2 {
  margin: 0 0 8px;
  font-size: 1.05rem;
}

.result-card p {
  margin: 6px 0;
  display: flex;
  justify-content: space-between;
  gap: 12px;
}

.result-note {
  margin-top: 10px;
  min-height: 18px;
  font-size: 0.85rem;
  color: #6b7280;
}

@media (max-width: 720px) {
  body {
    padding: 14px;
  }

  .results-grid {
    grid-template-columns: 1fr;
  }
}